WilliamdeRos, 6th Lord de Ros of Helmsley was born circa 1369.2 He was the son of ThomasdeRos, 4th Lord de Ros of Helmsley and BeatricedeStafford.3 He and Margaretd'Arundel obtained a marriage license on 9 October 1394.2 He died on 1 September 1414.2 He succeeded as the 6th Lord de Ros of Helmsley [E., 1299] on 6 August 1393.2 He was appointed Privy Counsellor (P.C.)2 He held the office of Lord Treasurer from 1403 to 1404.2 He was appointed Knight, Order of the Garter (K.G.) in 1404.2